Abstract

Two methods are proposed for assessing the total concentration (c_Ar) of the most toxic hydrocarbons (arenes) in wastewaters. The procedures include the extraction of petroleum products with n-hexane, the adsorption purification of the extract from phenols, and the measurement of the absorbance of arenes in the UV region. No separation of alkanes and cycloalkanes is required. The first method enables the rapid estimation of c_Ar in terms of the standard substance X_st (o-xylene or m-xylene) for screening purposes. Absorbance is measured at 250 nm, which decreases the effect of intragroup selectivity and phenols remaining in the extract. The total concentrations of arenes in n-hexane solutions are estimated by this method rather accurately (error δc < 7% at RSD < 5%). However, the analysis of aqueous solutions (wastewater simulant solutions) in the range of c_Ar from 0.1 to 50 mg/L leads to δc > 50%. The results of c_Ar estimation in simulations and wastewaters are underestimated, which is mainly due to the loss of arenes during sample preparation. Using the second (more accurate) method, the absorbance of the extract is measured at seven wavelengths in the region 240–280 nm. The c_Ar value is found by multiple linear regression without recalculation to X_st. Multivariate calibrations are constructed using extracts from 25 simulated solutions (training set) and passing them through all sample preparation operations, which decreases the loss of analytes. At c_Ar > 1 mg/L, the error in the analysis of simulants from the test set does not exceed 20% at RSD < 12%. The duration of analysis is 1 h. The procedure was tested in the analysis of wastewaters from enterprises of various profiles. The results agree with the results of chromatographic analyses of the same samples.

中文翻译：

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紫外光谱法测定废水中芳烃的总浓度

摘要

提出了两种方法来评估废水中毒性最强的碳氢化合物（芳烃）的总浓度 ( c _Ar )。该程序包括的石油产品与萃取Ñ正己烷，从酚提取物的吸附纯化，并在UV区域中芳烃的吸光度的测定。不需要分离烷烃和环烷烃。第一种方法能够快速估计Ç_的Ar中的标准物质X而言_ST（Ò二甲苯或米-二甲苯）用于筛选目的。在 250 nm 处测量吸光度，这会降低组内选择性和提取物中残留的酚类的影响。在芳烃的总浓度Ñ己烷溶液通过该方法（误差δ而精确地估计Ç在RSD <5％<7％）。然而，对c _Ar范围为0.1 至 50 mg/L的水溶液（废水模拟溶液）的分析导致 δ c > 50%。c _Ar的结果模拟和废水中的估计值被低估，这主要是由于样品制备过程中芳烃的损失。使用第二种（更准确）的方法，在 240–280 nm 范围内的七个波长处测量提取物的吸光度。所述Ç_氩值由多元线性回归，而不重新计算至X发现_ST。多变量校准是使用 25 种模拟溶液（训练集）的提取物构建的，并将它们传递给所有样品制备操作，从而减少分析物的损失。在Ç_氩> 1 mg/L，在 RSD < 12% 时，对来自测试集的模拟物的分析误差不超过 20%。分析持续时间为 1 小时。该程序在不同类型企业废水的分析中进行了测试。结果与相同样品的色谱分析结果一致。